1. Field of the Invention
The present invention relates generally to side shift carriage attachments which attach to the conventional lift carriage of a lift truck and more specifically to a quick coupling device for connecting the side shift cylinder of such an attachment to the lift carriage of the truck.
2. Description of the Prior Art
A conventional lift truck front carriage includes a pair of vertically spaced horizontal cross frame members to which conventional lift truck forks can be attached or removed for attachment of various other carriage attachments such as load rotators, side shift carriages and push-all mechanisms.
Side shift attachments are adapted to hook to the upper cross member of a conventional lift carriage and slide sideways therealong under the influence of a side shift cylinder connected at one end to the lift carriage and at the other end to the side shift attachment. Such side shift attachments have presented special problems heretofore because of the need to modify the lift carriage to provide a coupling device for attaching the side shift cylinder to it. Such prior coupling devices have been permanently connected to the lift carriage and have included portions projecting forwardly of the front of the carriage so as to interfere with the use of the lift carriage with other attachments such as lift forks, rotators and the like which require that the frontal portions of the carriage be unobstructed.
To eliminate the need for the foregoing-described use-restricting modification of the lift carriage to accept side shift attachments, so-called "false" carriages have been built, substantially duplicating the lift carriage and attachable thereto. The side shift cylinder coupling device is permanently attached to the false carriage, and the side shift attachment is hooked to the false carriage. The side shift carriage then shifts laterally along the false carriage. When the lift carriage is to be used with other attachments, the false carriage and its side shift attachment are removed therefrom. The disadvantage of this arrangement is that it reduces the load capacity of the lift truck because of the added weight of the false carriage and the increased moment arm of the load with respect to the front wheels of the truck. A further disadvantage of the false carriage arrangement is its increased cost as compared to the previously described arrangement.
From the foregoing it will be apparent that there is a need for a means for connecting the shift cylinder of a side shift attachment to the lift carriage of a lift truck without preventing use of the truck and its carriage with other attachments, without appreciable reduction in the load capacity of the attachment and while minimizing the cost of the connection.